The present invention is directed to a sheet of rolled wrapping material for use in an agricultural baler to securely wrap a harvested cylindrical bale. In the process of wrapping during the harvesting, the wrapping material must be securely bound to the bale's underlying, beginning perimeter end in order to ensure protection against the elements in the field. Secondly, there must be a mechanism within the wrapping material to separate the active wrapping segment for the bale from the available wrapping material on a roll contained in the baler. Presently available wrapping materials include rolls of individual wrapping segments successively joined via elaborate Z-folds including multiple interacting adhesive layers to form an otherwise ‘continuous roll’ of segments. Further, the trailing end of each segment, as part of the Z-fold, has an adhesive surface to seal the end of the wrap on the bale to the wrapping surface immediately beneath it. (See U.S. Pat. Nos. 6,787,209 and 7,541,280)
In addition to multiple issues with the various adhesive layers in respect of securing the wrapping segments successively together and securing the tail end of the wrap segment to the bale, there are additional issues with the security of the wrap in respect of the exposure of the wrapped bale to temperature swings, wind and rain such that the present material is less than totally satisfactory. There are also issues of individual wrapping portions (segments) becoming entangled in the wrapping machinery due to premature separation and/or exposure to the adhesive systems. Adding further to the issues is the cost of the manufacture of the multi-segmented roll of wrapping material.
The present invention is directed to a wrapping system including a continuous sheet of wrapping material, rolled on a roller which may be unrolled to envelope a rolled bale. The wrapping material of the present invention has wrapping segments identified by the periodic disposition of a transverse line of slits or a scoring in the material placed uniformly along its length to identify wrapping segments. The effect of the series of slits or scoring in the transverse line is to weaken the material along a proposed parting line to enable the separation during a wrapping segment. A satisfactory result is achieved in machines such as illustrated in the patents identified above with a total of about 25 percent of the substrate slit by means of a plurality of small individual slits generally uniformly placed in the pmposed parting line. It is also notable that slit line configurations should not be limited to straight line slitting or scoring perpendicularly oriented across the web of wrapping material. For example, the configuration of the transverse parting line may be one or more connected, angular and/or curved segments. Likewise, depending upon the line configuration and length, the length of the slits may be varied.
Alternatively to the lines of independent slits which penetrate through the material, it has been discovered that the searability of the wrapping segments may be accomplished with a transverse line wherein the surface of the material has been scored with a blade, chisel or the like whereby the surface of the wrapping material has been weakened for separation. The scoring is accomplished by pulling a sharp edge across the material, creating a gouging which leaves a chamfer, trough or valley in the material substrate. This weakens the wrapping material similarly to the slits at the separation location such that the linear pull of the material causes a separation on the line of scoring or gouge, providing an effective separation at the desired location. The depth of the score or gouge is chosen such that sufficient strength remains in the wrapping material for normal handling, loading and manufacturing processes. The depth of scoring will vary depending upon the type, and thickness of the wrapping material, but a depth of about 10 percent of the material thickness is normally sufficient, but from 5 percent to about 50 percent may be satisfactory depending upon internal stresses imposed by the particular bailing machine imposed in the process and the thickness of the wrapping material.